Crimping tool

ABSTRACT

AN IMPROVED TOOL USED FOR CRIMPING A PRIMER IN THE END OF A CARTRIDGE CASING. THE TOOL INCLUDES A BODY MOUNTED ON A RECIPROCALLY MOVABLE PRESS PLATEN. THE TOOL BODY HAS A BORE FORMED THEREIN, AND A PUNCH ASSEMBLY IS MOUNTED WITHIN THE BORE. A CHAMBER IS DEFINED WITHIN THE CLOSED END OF THE BORE, AND MORE PARTICULARLY, BETWEEN THE CLOSED END OF THE BORE AND THE INNER END OF THE PUNCH ASSEMBLY. DURING THE OPERATION OF THE TOOL, THE CHAMBER IS FILLED WITH PRESSURIZED HYDRAULIC FLUID. THIS FLUID IN THE CHAMBER PERMITS MOVEMENT OF THE PUNCH ASSEMBLY, RELATIVE TO THE TOOL BODY, DURING THE PORTION OF THE STROKE OF THE PRESS PLATEN DURING WHICH THE PUNCH ASSEMBLY IS IN CONTACT WITH THE CARTRIDGE CASING. THE CHAMBER IS CONNECTED WITH A PRESSURIZED FLUID RESERVOIR WHICH, IN THE PREFERRED EMBODIMENT, IS MOUNTED ON AND MOVES WITH THE BODY. THE RESERVOIR IS FINNED TO ASSIST COOLING THE FLUID THEREIN, AND THE FLUID PASSAGES WHICH INTERCONNECT THE RESERVOIR AND THE CHAMBER ARE FORMED IN THE TOOL BODY SO AS TO MINIMIZE THE POSSIBILITY OF ANY LEAKAGE OF PRESSURIZED FLUID AND TO MINIMIZE MAINTENANCE OF THE TOOL.

March 13971. T.- s. ZASTROW CRIMPING TOOL S Sheets-Sheet 2 Filed Jan. 2,1969 INVEN'IOR. 72/0/1446 6? ZAJTQOW United States Patent 3,568,291CRIMPING TOOL Thomas S. Zastrow, St. Paul, Minn., assignor to RemmeleEngineering, Inc., St. Paul, Minn. Filed Jan. 2, 1969, Ser. No. 788,551Int. Cl. 1323p 19/00 U.S. Cl. 29-200 Claims ABSTRACT OF THE DISCLOSUREAn improved tool used for crimping a primer in the end of a cartridgecasing. The tool includes a body mounted on a reciprocally movable pressplaten. The tool body has a bore formed therein, and a punch assembly ismounted within the bore. A chamber is defined within the closed end ofthe bore, and more particularly, between the closed end of the bore andthe inner end of the punch assembly. During the operation of the tool,the chamber is filled with pressurized hydraulic fluid. This fluid inthe chamber permits movement of the punch assembly, relative to the toolbody, during the portion of the stroke of the press platen during whichthe punch assembly is in contact with the cartridge casing. The chamberis connected with a pressurized fluid reservoir which, in the preferredembodiment, is mounted on and moves with the body. The reservoir isfinned to assist cooling the fluid therein, and the fluid passages whichinterconnect the reservoir and the chamber are formed in the tool bodyso as to minimize the possibility of any leakage of pressurized fluidand to minimize maintenance of the tool.

BACKGROUND OF THE INVENTION This invention relates to an improvedcrimping tool, and more specifically, to an improved tool for crimpinga. primer in the end of a cartridge casing.

In the past, cartridge cases, and particularly .30 caliber cartridgecases, have been manufactured in a multi-step process. In this process,the cartridge cases to be manufactured are placed on separate mandrelsand the mandrels are adapted to be sequentially moved to a plurality ofwork stations beneath a reciprocally movable platen of a press. Thepress platen has a plurality of tools mounted thereon which are utilizedto perform various operations or steps on the cartridge casing inconnection with the manufacture of the. casing.

The tool previously used for crimping primers in the ends of cartridgecasings in such a process included a punch and Bellville spring assemblywhich were mounted on the press platen. The spring assembly waspositioned so as to permit limited relative movement of the punch withrespect to the press platen during the time the punch was in contactwith the cartridge casing. The spring assembly was necessary because thethickness of the end walls of the cartridge casings is not set, forth inthe government specifications and some variation in the end Wallthickness occurs.

However, there have been several problems with this prior crimping tool.To achieve satisfactory operation, i.e., to produce finished cartridgecasings within the rigid government specifications, the setting of thespring assembly had to be frequently and carefully adjusted to preventdefective casings from being manufactured. The required checking of theadjustment and the adjustment itself were time consuming and thusincreased the cost of manufacturing the casings. Also, even whenproperly adjusted, the prior crimping tool often would cause minutecracking in the end Walls of the casings or other defects, and if theprimer had not been properly positioned in the preformed cavity in theend wall, the tool 3,568,291 Patented Mar. 9,1971

could not correctly crimp the primer in the casing. Any manufacturingdefects in the cartridge casing are significant in view of the stringentgovernment specifications.

SUMMARY OF THE INVENTION In contrast, the improved crimping tool of thepresent invention provides satisfactory, substantially defect-freeoperation and significantly minimizes, relative to the prior tools, theamount of the maintenance, and the frequency of adjustment required forsatisfactory operation. The crimping tool of the present inventionincludes a tool body which is mounted on and carried by the press platenand which has a bore formed therein so that the central longitudinalaxis of the bore is coaxial with the central longitudinal axis of thecartridge casing to be crimped by the tool. A punch assembly, includinga punch, is mounted in the bore so that a chamber is formed in the borebetween the assembly and the closed end of the bore. Durirtg operation,the chamber is maintained full of pressurized fluid therein permit thepunch assembly to move relative to the tool body during the time thepunch is in contact with the cartridge casing.

The use of the hydraulic chamber provides unexpectedly advantageousresults in that the punch may be in contact with the cartridge casingduring a significantly longer portion of the stroke of the press platen.This permits the punch initially to contact the casting at a highervelocity and provides superior Work hardening and cold workingcharacteristics.

In the preferred embodiment, a pressurized fluid reservoir is alsomounted on and carried by the tool body so that the reservoirreciprocally moves with the press platen. The reservoir has a pluralityof fins formed thereon to assist in cooling of the fluid in thereservoir. The tool body also includes a plurality of passagesinterconnecting the reservoir and the chamber, and these passagesminimize the possibility of leakage of pressure fluid from the tool bodyand minimize maintenance of the tool.

A relief and check valve combination is positioned, in the preferredembodiment, within the reservoir and is used for controlling the flow offluid to and-from the chamber in the bore. The reservoir is alsoconnected With an external source of gas or air under pressure, and thecoupling interconnecting the air hose and the reservoir is arranged anddesigned so as to be easily removable so that when removed, an adjustingtool may be inserted in the reservoir for the purpose of adjusting thesetting on the valve assembly.

In some embodiments, and particularly those tools wherein a relativelylarge volume of hydraulic fluid is displaced because, for example, thebore, and thus the chamber, has a relatively large diameter and/ or thespeed of the press is relatively high, the passages in the tool body maybe formed and arranged so that the fluid may be recirculated between thereservoir and hydraulic chamber so as to minimize the heating of thefluid in the cham- :ber. This recirculation of the fluid also helps todisperse any foreign material which may get into the fluid.

Accordingly, it is one of the principal objects of the present inventionto provide an improved tool for crimping the primers in the ends ofcartridge casings. A related object of the present invention is toprovide an improved tool of the type described wherein the tool includesa chamber formed in the tool body between the punch assembly and thetool body, and wherein the chamber permits the punch assembly to moverelatively with respect to the tool body and significantly improves theoperation of the crimping tool.

Another object of the present invention is to provide an improved toolfor crimping primers in the ends of cartridge casings wherein thecrimping tool is mounted on and carried by a reciprocally movable pressplaten; wherein the tool includes a bore whose central longitudinal axisis coaxial with the central longitudinal axis of the cartridge casing tobe crimped; wherein the punch assembly is mounted in the bore; wherein achamber is formed in the closed end of the bore between the punchassembly and the closed end of the bore; wherein the chamber ismaintained full of pressurized fluid; and wherein the chamber and punchassembly are arranged so that the punch assembly may move relativelywith respect to the tool body during the time the punch assembly is incontact with the cartridge casing.

Still another object of the present invention is to provide animprovedtool for crimping primers in the ends 'of' cartridge casings wherein apressure reservoir is mounted on the tool, and thus on the press platen,for

-movement therewith; wherein the tool body has a num- -ber of passagesformed therein which interconnect the ture therein which is normallyadapted to be closed by a coupling means for connecting the reservoir toa source of pressurized gas or air and which is designed so that whenopen, accessto the valve means in the reservoir for adjustment thereofis permitted through the aperture. A

further related object of the present invention is to provide animproved tool of the type described wherein fluid passages in the toolbody are arranged to permit recirculation of the fluid between thereservoir and the chamber so as to assist in cooling the fluid in thechamber.

These and other objects of the present invention will become apparentfrom the following description of the preferredembodiment and theappended claims.

DESCRIPTION OF THE DRAWINGS FIG, 1 is a partial, verticalcross-sectional view of the improved tool of the present inventionshowing the tool mounted on a press platen and positioned above acartridge casing to be manufactured.

FIG. 2 is a vertical cross-sectional view of a portion of the improvedtool of the present invention showing the details of the punch assemblyand chamber.

FIG. 3 is a partial, vertical, cross-sectional view taken along thelines 33 in FIG. 1.

FIG. 4 is a partial, cross-sectional view of a modified embodiment oftheimproved tool of the present invention showing a modified chamber andinterconnecting passage arrangement.

FIG; 5 is a diagram showing the position of the press platen and thusthe improved tool of the present invention, with respect to time duringa stroke of the press platen.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1, 2 and3, the improved tool of the. present'invention comprises a body, showngenerally at 11, whichincludes a generally cylindrical member, 12 .andan arm 13. A plurality of bolts, one being shown at 14, areused to mountthe body 11 on a platen of a press, not shown, so that the uppercylindrical .member 12 of the body is positioned in a cylindricalselected rate, e.g., one hundred strokes per minute, in a conventionalmanner. Also, as noted above, the press platen 15 may have a number ofother tools mounted thereon which are utilized in the manufacture ofcartridge casings, and the body 11 would be mounted on the press platenwith respect to these other tools so that there is no interference orcontact between the various tools.

A pressurized reservoir 17 is mounted on the upper face 18 of the arm 13by a plurality of bolts, not shown, so that the reservoir 17 movesreciprocally with the press platen 15 and so the reservoir 17 ismaintained vertical, as shown, during operation of the press. A central,circular aperture 21 is formed in the lower end 22 of the reservoir 17.A conventional O ring seal 23 is positioned in a groove 24 about theaperture 21 and forms a seal between the lower end 22 of the reservoirand the upper face 18 of arm 13. The upper end 25 of the reservoir 17has a threaded opening 26 formed therein. A conventional fitting 27 isnormally threaded into the opening 26 and includes a quick-disconnectcoupling 27 which is adapted to be connected to the coupling end 28 ofan air hose 29. The hose 29 is connected at its other end, not shown,with a source of air or gas under pressure. While the pressure of theair or gas may vary, normally air or gas under a pressure of pounds persquare inch is sufficient to permit satisfactory operation of the tool.

A plurality of fins 31 are integrally casted on the outer surface of thereservoir 17 and are designed to assist in cooling the fluid in thereservoir by increasing the. rate of heat transfer during the movementof the reservoir with the press platen 15.

As best shown in FIGS. 1 and 3, the arm 13 includes a centrally located,horizontally disposed passage or bore 32 which extends from the member12 to the outer end 33 of the arm. A centrally located, verticallydisposed passage or bore 34 intersects the passage 32 and its upper,threaded end 35 opens into the interior 36 of the reservoir with thelongitudinal central axis of the passage 34 being coaxial with thecenter of the aperture 21 and perpendicular to the central longitudinalaxis of the passage 32. A second off-set vertical passage or bore 37 isformed in the arm parallel to, but spaced from, the passage 34. Thepassage 37 also opens into the interior 36 of the reservoir 17 with theaperture 21. A transverse passage or bore 38 .is formed in the arm 13below the passage 32, and with the central longitudinal axis of thepassage 38 being perpendicular to the plane including the centrallongitudinal axes of the passages 32 and 34. A counterbore 39interconnects the inner ends of passages 37 and 38; and a counterbore 41interconnects the passages 32, 34 and 38.

The outer threaded end 42 of the passage 38 is closed by a plug 43 andflow through the counterbore 39, from passage 37 to passage 38, iscontrolled by a one-way valve 44 positioned within the passage 38. Thevalve 44 consists of a ball 45 which has a diameter greater than thediameter of counterbore 39 and which is adapted to seat against theshoulder 46 formed between the inner end of the passage 38 and thecounterbore 39 so that when the ball is seated, the flow of fluid fromthe passage 37 to the passage 38 through counterbore 39 is prevented.The ball 45 is urged against the shoulder 46 by a coil compressor spring47 that is positioned between the plug 43 and the ball. As a result ofthe use of the valve 44, fluid may flow from passage 37 to passage 38,but cannot flow from passage 38 to passage 37. p

A high pressure relief valve assembly 48 is threaded into the upper end35 of the passage 34. The relief valve assembly 48 projects through theaperture 22 and into the interior 36 of the reservoir 17 and is designedand arranged to permit flow of fluid from the passage 34, and

thus passage 32, into the interior 36 of the reservoir 17,

only after the pressure of the fluid in these passages exceeds apreselected value. The positioning of the valve assembly 48 in thereservoir 17 reduces the chances of unauthorized tampering with thevalve assembly.

The relief valve assembly 48 includes a housing 49 having a centrallypositioned, coaxial bore 51 and counterbore 52 formed therein, with ashoulder 53 being formed therebetween. A plug 54 is threaded into andblocks the upper end of the bore 51 and the upper end 55 of the housing49 is flared outwardly, as shown, for the reason more fully describedhereinafter. The counterbore 52 communicates with the passage 34 and aplurality of relatively small diameter bores, two of which beingindicated at 55, to permit communication between the bore 51 and theinterior 36 of the reservoir. Flow of fluid from the counterbore 52 tothe bore 51 is controlled by a ball 56 which has a diameter larger thanthe diameter of counterbore 52 but smaller than the diameter of bore 51,and which is adapted to seat against the shoulder 53. A coil compressionspring 57 is positioned in the bore 51 between the plug 54 and a back-upplate 58 adjacent to and abutting the ball 56 so that the spring 57urges the ball 56 tightly against the shoulder 53. As noted above, thearrangement of the ball 56 and spring 57 prevents fluid from flowingfrom the reservoir 17 into the passage 34, and thus the passage 32,while permitting flow from the passage 34 to the reservoir only when thepressure of the fluid in the passages exceeds a preselected value.

The bias of the spring 57 may be changed by adjusting the position oftheplug 54, relative to the housing 49. To facilitate making such anadjustment, the central longitudinal axis of the valve assembly 48 iscoaxial with the center of the opening 26 so that when the fitting 27 isremoved from the reservoir, a long-handled tool, such as a screwdriver,may be inserted through the opening 26 and used to adjust the positionof the plug 54. The flared outer end 55 of the housing 49 assists inguiding and locating the end of the screwdriver with respect to theplug.

As noted above, the passage 32 extends to the end 33 of the arm. Theouter end 59 of the passage is counterbored at 61 and is threaded toreceive a conventional fitting 62 which is adapted to be connected to aconventional fluid pressure sensing instrument, not shown, for thepurpose of ascertaining the pressure of the fluid in passage 32.

As shown in FIG. 1, a mandrel 6-3 is positioned immediately below themember 12 and is supported by the mandrel support structure showngenerally at 64. A cartridge casing 65 is positioned on the mandrel andis supported midway between its ends by the guide 66 which may be a partof the structure 64. The upper closed end 67 of the casing includes apreformed primer cavity 68, and a primer 69 is shown positioned in thiscavity. The diameter of the cavity 68 is slightly greater than thediameter of the primer 69 so, as shown, the primer is not secured withinthe cavity. As noted above, in conventional manufacturing setups, themandrel 63 may be moved, relative to the press platen 15, so thatvarious manufacturing operations may be performed on the casing 65 whileit is mounted on the mandrel 63. The mechanism required to move themandrel with respect to the platen is conventional, and for this reasonthe mechanism is not shown and further description thereof has not beenincluded herein. However, it should be noted that a man- 7 drel 63 witha casing 65 positioned thereon is always fixedly positioned below themember 12 when the press platen 15 has moved downward a sufficientdistance so that there is contact between the tool and the casing.

Referring now to FIG. 2, the member 12 has a central bore 71 formedtherein so that when the mandrel 63 is positioned, as shown in FIG. 1,the central longitudinal axes of the bore 71 and the mandrel 63, andthus the casing 65, are coaxial.

A punch assembly, shown generally at 72, is positioned in the bore '71.The punch assembly 72 consists of an annular retainer 73 which, in part,is positioned within the bore 71 and which is secured to the bottomsurface 74 of the portion 12 by a plurality of bolts, not shown, thatextend through the shoulder 75 of the retainer. The retainer '73 has acentral bore 76 formed therein, and the outer diameter of the shoulder75 is substantially equal to the outer diameter of the adjacent part ofthe member 12, although a part of the shoulder 75 is cut away as shownat 77.

An annular, elongated guide 78 is positioned within the bore 76. Theguide 78 has a shoulder 79 formed at its upper end, with the outerdiameter of the shoulder 79 being greater than the diameter of bore 76but less than the diameter of bore 71. The guide 78 is secured withinthe retainer 73 by the shoulder 79. A screw 81 is fastened to the lowersurface 82 of the retainer 73 and the head of this screw extends into agroove 83 formed in the lower end 84 of the guide so as to prevent theguide 78 from rotating, relative to the retainer. The end 84 of theguide, as shown, is cut away and flared outwardly so that the end 84cannot contact the cartridge casing 65.

The guide 78 has a central longitudinal bore 85 formed therein with theupper portion 86 thereof being threaded. A first transverse bore 87 isformed in the guide and intersects the portion 86 of the bore 85. Asecond transverse bore 88 is also formed in the guide and intersects thelower, smooth-sided portion 89 of the bore 85.

A generally cylindrical punch 91 is positioned in the lower portion 89of the bore 85. The punch 91 is of conventional design and is arrangedin the bore 85 so that its lower end 92 projects from and beyond thelower end of the bore 85. The lower end 92 of the punch is formed sothat when the punch '91 is brought into contact with the end 67 of acartridge casing 65, the punch will force or extrude the metal adjacentthe primer cavity 68 around and adjacent to the primer 69 so as tosecure the primer within the cavity 68.

The punch 91 is secured within the bore 85 by a set screw 93 which isthreaded in the bore '88. The position of the punch 91, relative to theguide 78, i.e., the distance the lower end 92 of the punch projectsbeyond the lower end of the bore 85, is regulated by a pair of setscrews 94 and 95, which are threaded, end-to-end, in the upper portion86 of the bore '85. A set screw 96, threaded in the bore 87, is used tolock the set screws 94 and 95 in place in a conventional manner, oncethe correct position of the set screws 94 and 95 has been established.

The punch assembly 72 also includes a disc or piston 97 which ispositioned on the upper surface of the guide 78. The disc 97 may be madeof metal and has a diameter substantially equal to the diameter of bore71. A transverse bore 98 is formed in the member 12 and Vents theannular space 99 in the bore 71 defined by the upper end of the retainer73, the lower surface of the disc 97 and the shoulder 79 of the guide78. A conventional cup seal 101 is positioned on the upper face of thedisc 97 and has a diameter substantially equal to the diameter of thebore 71. The seal 101 is adapted to minimize leakage of fluid betweenthe seal and the bore 71.

A chamber 102 is defined in the upper end of the bore 71 between theseal 101 and the inner end wall 103 of the bore. The chamber 102communicates, through a bore 104 in the end wall 103, with a transversepassage 105. As shown in FIG. 2, the left end of the bore 105 is blockedby a threaded plug 106 and the right end thereof communicates with theupper end of a vertical bore 107. The lower end of the bore 107 isblocked by a threaded plug 108, and the bore 107 is intersected by theleft end of the liore 32 which, as noted above, is formed in the arm 3.

FIG. 4 shows a modified tool wherein the passage arrangementinterconnecting the chamber in the member 12 of the tool with thereservoir 17 has been changed. More specifically, a pair of passages 111and 112 communicate with the chamber 113 at spaced points. Passage 111communicates with check valve 44 and permits fluid to fiow from thereservoir 17 into the chamber 113. Passage 112 communicates with therelief valve assembly 48 and when the pressure in chamber 113 andpassage 112 upstream from the assembly 48 exceeds the preselected biasof the spring 57, permits fluid to flow from the chamber 113 into thereservoir 17. In this modified tool, there is no fluid communication,such as provided by bore 41, between the passages 111 and 112. The endsof the passages 111 and 112 which communicate with the chamber 113 arearranged with respect to the chamber so that there is continualrecirculation of the fluid in chamber 113, i.e. the fluid in chamber 113which has become heated as a result of the operation of the tool isreturned to the reservoir while fresh, relatively cooler fluid isintroduced into the chamber 113 from the reservoir, during operation ofthe tool. This recirculation of the fluid keeps the temperature of thefluid in chamber 113 relatively low. Thus this modified passagearrangement is particularly advantageous in tools in which a relativelylarge volume of fluid is displaced per unit time, such as when thechamber 113 has a relatively large diameter and for when the tool isutilized on a high speed press, e.g., a press operating at three hundredstrokes per minute. Also,

the recirculation of the fluid helps to dispense any foreign materialwhich may get into the fluid.

Operation The operation of the improved tool of the present invention isas follows: Initially and as a result of the air or gas pressure in theupper part of reservoir 17, the chamber 102, and the passages connectingthe chamber with the reservoir are completely filled with hydraulicfluid. This causes the punch assembly 72, and thus the punch 91, to bein its lowermost position. When the end '92 of the punch 91 initiallycomes into contact with the cartridge casing 65, the upward force on thepunch 91, and thus on the punch assembly 72 including the disc 97,causes the pressure of the fluid in the chamber 102 to increase. Furtherdownward movement of the press platen 15, and thus the punch 91, furtherincreases the pressure in the chamber 102, and thus in passages 105,107, 32, 34 and 52, until the setting of the relief valve assembly 84 isreached, the ball 56 is unseated and fluid is permitted to escape fromthe chamber 102 and passages 105, 107, 32, 34 and 52 into the reservoir.This escape of fluid through the relief .valve assembly 48 permits thepunch assembly 74 .to move upwardly in the bore 71 relative to themember 12 and in effect, extends the working time of the punch 91, i.e.the time the punch 91 is in contact with the casing. As the press platen15 moves away from the bottom-dead-center point, a volume of relativelycool fluid is drawn into the chamber 102 from the reservoir through thecheck valve 44 to replenish the fluid forced into the reservoir 17through relief valve assembly 48.

As noted above, the significant amount of controlled relative movementof the punch 91 permits the punch to be brought into contact with thecasing 65 at a much earlier point during the downward portion of thepress stroke. This permits the punch 91 initially to strike the end 67of the cartridge casing at a much higher velocity and provides bettermetal cold working and work hardeniug of the casing. Furthermore,apparently the relative movement of the punch, with respect to themember 12, also permits the punch to correct angular misalignments ofthe primer 69 in the cavity 68.

FIG. shows a diagram of the time-position of the press platen 15 duringone complete stroke and is included herein to illustrate the differencebetween the points of initial contactbetween the punch and the cartridgecasing when the improved tool of the present invention is used and whena prior crimping tool is used. More specifically, the arrow 114indicates the direction of movement of the platen, the point 115 thetop-dead-center point of the press platen, and point 116 thebottom-dead-center point of the press platen. The point 117 indicatesthe time during the stroke when the punch 91 first contacts the end 6-7of the casing 65 when the improved tool of the present invention isused; Whereas, the point 118 indicates the time during the stroke whenthe punch first can be brought into contact with the end 67 of thecasing, without defective crimping, when the prior crimping tools areutilized. As will be apparent from this diagram, the punch is in contactwith the casing, i.e., the work time of the 10 punch, approximately fivetimes longer when the improved tool of the present invention is used ascompared to when the prior crimping tools are utilized.

It has been found that satisfactory results may be obtained whenpressure of the hydraulic fluid in the tool,

i.e., in the chamber 102 and in passages 105, 107, 32, 34

and 52, is between 800 and 2500 p.s.i. during that portion of the strokeduring which the punch 91 is in contact with the cartridge casing. Also,as noted above, satisfactory results have been obtained if the air orgas introduced into the upper portion of the reservoir is under 80p.s.i. pressure. It is important, however, that the reservoir 17 bemaintained vertically, as shown, and that a sufiicient volume ofhydraulic fluid is always maintained in the reservoir so that no air orgas is able to get into the chamber 102 or the passages interconnectingthe chamber and the reservoir. In this connection, the level of thehydraulic fluid in the reservoir should always be maintained well abovethe upper end of relief valve assembly 48.

In view of the foregoing, it is apparent that the improved tool of thepresent invention provides significant and unexpected advantages overthe prior crimping tools in that it reduces the number of defectivecasings manufactured; reduces the amount of time required for adjustingand maintaining the tool; and improves the quality of the finishedcartridge casing as a result of the superior cold working and workhardening of the casing during the crimping operation.

Obviously, modifications can be made in the improved tool of the presentinvention. For example, the reservoir would not have to be mounted onand carried by the press platen but could be mounted at a fixed locationadjacent to the platen and connected with the tool by means of flexiblehoses. The ditficulty with such a fixed mounting is that repeated usage,e.g., approximately one hundred strokes per minute, causes the flexiblehoses to wear out relatively quickly and this increases maintenance.Also, the passages interconnecting the chamber and the reservoir wouldnot have to be formed within the arm 13 but could be separate conduitsor tubes fastened to the arm. However, it is believed preferable to formthese conduits or passages integrally with the arm so as to minimize thepossibility of leakage of the high pressure fluid. Likewise, thespecific arrangement of the components of the punch assembly, of course,could be changed. For elisrample, the disc 97 could be directly securedto the guide Thus, since the invention disclosed herein may be embodiedin other specific forms without departing from 0 the spirit and generalcharacteristics thereof, embodiments described herein are therefore tobe considered in all respects as illustrative and not restrictive, thescope of the invention being indicated by the appended claims, ratherthan by the foregoing description; and all changes 5 which come withinthe meaning and range of equivalency of the claims are thereforeintended to be embraced therein.

I claim as my invention: 1. Apparatus for crimping a primer in the endof a cartridge case comprising: a body adapted to be secured to a pressplaten which is reciprocally movable through a fixed stroke, the bodyhaving a bore formed therein so that the central longitudinal axis ofsaid bore is parallel to the direction of the motion of the press platenand coaxial with the central longitudinal axis of the cartridge case,

said bore having an open end and a closed end; punch means positioned insaid bore for relative movement therein in a direction parallel to thecentral longitudinal axis of said bore, the punch means including, atone end thereof, a punch which, in part, projects from the open end ofsaid bore and is adapted, during a portion of the stroke of the pressplaten, to contact the end of the cartridge casing in which the primeris to be crimped, the punch being positioned so that its centrallongitudinal axis is coaxial with the central longitudinal axis of thecartridge case during at least said portion of said stroke; means forretaining the punch means within said bore, said bore defining a chamberbetween said closed end of said bore and the other end of the punchmeans; a pressurized fluid reservoir; passage means connecting saidchamber with the fluid reservoir; valve means for controlling the flowof fluid between said chamber and the fluid reservoir and between thefluid reservoir and said chamber so that said chamber and passage meansare filled with fluid and so that the pressure of the fluid in saidchamber and passage means is always below a preselected, relatively highpressure whereby during said portion of said stroke the punch means maymove, relative to the body, toward the closed end of said bore andwhereby during the remainder of said stroke, the punch means is movedtoward said open end of said bore.

2. The apparatus described in claim 1 wherein the fluid reservoir moveswith the press platen.

3. The apparatus described in claim 2 wherein the fluid reservoir ismounted on the moves with the body; and wherein the passage meansincludes passages formed in the body.

4. The apparatus described in claim 3 wherein a plurality of fins areformed on the exterior surface of the fluid reservoir and are designedto assist in the cooling of the fluid reservoir.

5. The apparatus described in claim 1 wherein the passage means includesat least two separate passage means interconnecting said chamber and thefluid reservoir so that the fluid in said chamber is recirculated duringoperation of the apparatus.

6. The apparatus described in claim 1 wherein the valve means includes ahigh pressure relief valve which is mounted within the fluid reservoirand which controls the flow of fluid from said chamber to the fluidreservoir.

7. The apparatus described in claim 6 wherein the fluid reservoir isconnected with a source of pressurized gas by means of a removablefitting which is normally secured in an opening in the fluid reservoir,and which may be removed so that adjustment of the high pressure reliefvalve may be made through said opening.

8. The apparatus described in claim 1 wherein the punch means includes apiston and seal which are positioned in said bore adjacent to saidchamber; and wherein the punch means includes means for adjusting theamount the punch projects from said open end of said bore.

9. The apparatus described in claim 1 wherein the fluid reservoir isfastened to and moves with the body; wherein a plurality of fins areformed on the exterior surface of the fluid reservoir to assist in thecooling of the fluid reservoir; wherein the passage means includespassages formed in the body; wherein the valve means includes a highpressure relief valve which is mounted Within the fluid reservoir andwhich controls the flow of fluid from said chamber to the fluidreservoir; wherein the fluid reservoir is connected with a source ofpressurized gas by means of a removable fitting which is normallysecured in an opening in the fluid reservoir, and which may be removedso that adjustment of the high pressure relief valve may be made throughsaid opening; wherein the punch means includes a piston and sealwhichare positioned in said bore adjacent to said chamber; and whereinthe punch means also includes means for adjusting the amount the punchprojects from said open end of said bore.

It). The apparatus described in claim 9 wherein the passage meansincludes at least two separate passages interconnecting said chamber andthe fluid reservoir so that the fluid in said chamber is recirculatedduring operation of the apparatus.

References Cited UNITED STATES PATENTS THOMAS H. EAGER, Primary ExaminerU.S. Cl. X.R. 291.31, 252

